Supporters of the Occupy Central movement hope to establish a "transparent and credible" mechanism to decide how and when the occupation should be called to an end, amid worries the civil disobedience protest could turn violent.

The organisers' remarks came a day after veteran China-watcher Ching Cheong, who backs the protest, voiced fears the action could result in bloodshed similar to what occurred in Tiananmen Square in 1989.

Speaking on a radio programme yesterday, Reverend Chu Yiu-ming, a core organiser of the movement, said establishing a "transparent and credible" mechanism was a major concern among the plan's backers, but it was not proving easy.

"They wanted to know whether we will have a mechanism to decide whether to go or to leave, and whether it will be transparent and credible. But at this point, I don't think anyone can answer that question," Chu said.

Associate law professor Benny Tai Yiu-ting, another proponent of Occupy Central, said the questions would be discussed in the coming months.

"If there's a real occupation, we will issue very good guidelines to our participants on how to ensure the action will be non-violent - that [each individual] must not only make sure [he or she] remained non-violent, but that they are also responsible for making sure other participants [don't get too agitated]," he said.

Tai first proposed the plan, now named "Occupy Central with Love and Peace", as a way to draw attention to the city's upcoming political reform for electing the chief executive by universal suffrage in 2017.

Occupy Central organisers have threatened to set up a road blockade of 10,000 protesters in the heart of the city in July next year if the government fails to deliver a reform package they find acceptable.

On Sunday, about 600 supporters attended the movement's first deliberation session and came up with seven priorities for the campaign, including elevating it to "a movement of all classes".

On the same day, Chief Executive Leung Chun-ying warned organisers there was "no possibility" it could be lawful or peaceful. The movement would be tolerated by neither the government nor the courts, he said.

That was followed by New World Development chairman Henry Cheng Kar-shun, who said that "no matter what Occupy Central was aimed at and how would it make use of loopholes in the law, it is illegal … and will affect Hong Kong's economic and financial order".

The Heung Yee Kuk also ran full-page advertisements in pro-Beijing newspapers, calling for the organisers to "give up the Occupy Central movement immediately and safeguard the city's social harmony and stability".

Tai said Leung's comment would only encourage more people to support the movement. The organisers planned to meet groups opposing the protest this month, he said.

This article appeared in the South China Morning Post print edition as Keeping mass rally peaceful is 'priority'